Dew point of benzene vapor and air mixture at 
 (a) 25 degree C and 750 mm Hg = 20 degee C 
 (b) 30 degree C and 750 mm Hg = 19 degree C 
 (c) 30 degree C and 700 mm Hg = 18.7 degree C
 Above results shows that the dew point does not depend on temperature but vary with the total pressure